<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        p::before {content:"第一章：";}
p::after {content:"Hot!";}
p::first-line {background:red;}
p::first-letter {font-size:30px;}
a:hover {color: #FF00FF}
p:first-child {color: red}
    </style>
</head>
<body>
    <H1>哈哈哈</H1>
    <iframe src="./promiseAll.html" frameborder="0"></iframe>
    <label for="mobile">Number:</label>
<input type="text" id="mobile"/>
<label>Date:<input type="text"/></label>
<a href="123">123</a>
<p>abc</p>
</body>
</html>